Lath board



151cv. so, 1948. Q A. BUTTRESS 2,455,016

LATH BOARD Filed April 11, 1944 Patented Nov. 30, 1948 o Frac 11 This invention relates toA allath board. andi pai-1- ticularly pertains to lath board of the "type embodying a layer of aplaster compositionr` inter'-l posed between cover sheets of fibrous material such as paper and in which the board is*l formed` with a series of apertures to receive and ei'ect'V a.v bond with plaster applied to the face of the board;V

The invention contemplates and has as one of its objects the provision of a construction lwhereby the portions ofthe outer fibrous coverl sheet. surrounding apertures in the sheetl will' be turned inwardly to overlie the. outer` end portions ofthe Walls surrounding the apertures. in the plaster layer and be at least partiallyl imbeddedtherenso as to anchor the portionsof the cover sheet surrounding the holes in the sheet inthe plaster" layer and reinforce the outer margin ofI the Walls of the plaster-receiving aperture and at the-same time present a neat and finished appearance.

Another object of the invention is to provide a construction at the inner end of the plasterreceiving apertures which while allowing a portion of' applied plaster enteringt-he apertures to` pass through the board, will inhibit or restrict the'` flow; of the plaster through the apertures' in a fashion to obviate or at least minimize waste of plaster due to flow of excessive quantities of thel plaster through the apertures.

A further object is to provide a` construction in the back cover sheet whereby" it is reinforced around the holes therein;

With the foregoing objects in view, together with such other objects and advantages asmay subsequently appear, the invention resides` in the parts and in the combination, construction and arrangement of parts hereinafter described and claimed, and illustrated by way of exampleai'nthe accompanying drawing; in which;

Fig. 1 is a view in elevation' of a fragmentary portion of a lath board as constructed in accordance with the invention;

Fig. 2 is an enlarged detail in section taken on the line 2-2 of Fig. 1 showing the manner of forming the plaster-receiving apertures;

Fig. 3 is a view of a fragmentary portion of the board as seen from the back thereof showing the manner of reinforcing the backing cover sheet around holes formed therein;

Fig. 4 is a view in vertical section showing the manner in which plaster is applied to the face of the board and as occupying the plaster-receiving apertures.

Referring to the drawings more specifically, A indicates generally a lath board comprising a layer 5 of plaster interposed between a palr of 2' fibrous cover'slreetsincluding: ag .front coversheet' 6 and a back cover sheet 1; the boardzAf being; formed with: a: seriesf 0.1i` apertures vB fory the reception of` plaster` 'Ehe-essence of. the irhlention"` resides in aimodeof;tashioningthe.-plaster-receiveing. apertures; B:

InacarryingA out the invention"A the' cover sheets- 6 and 1:arewformedwithiholes 8i and' 9' respectively whichy are1 smaller' than therholes ID in the"l plaster"` layer 5s' crosswisethereof.; whichflnilesl` 8;, 9l and I it arecentered':relativeftoieachf-other and are de-u signed:v to collectively form; the plastergreceivingivapertures B.

Y Invrorming. theboard:A the margins of;l the holes tlf-in.y the iront. cover sheet.- 6; arel turned inwardlyV and( downwardly' into they outer ends: ofA the holes.y I Il to extendover andibe'partia'lly imbeddedr in-l the outer endsof'the: plaster layer 5; themarginal portions H ot thaholes.- 8 being curved` inwardlyand thenA spread outwardly to: provideI rounded'.l margins I2# atlthe outer ends of; the apertures-B.J In order that themarginal portions Il conform.` tot the enla-rg,ementv of'f the.. holes llt theI margins- I=I split under strains imposed. thereonr dur-ing. stretching thereof` irr theV operationof: eitpa'lnsi-ing` themargins I I: thus" forming theI margins; I'lwith`A -afseriesi of tongues or flaps I4- which. are: readilfy partially irnbeddedin and' engagedy by the. plaster layer 5f. Irl-thisfashionithawallssurrounding the; apertures B hareformed; with beaded fibrous;- outer margins, whereby such margins are reinforced. anchorage of the marginal portions of the cover' sheetsurrounding theholes 8y in the-cover sheet 6 is. effected and!` a; neat and finished appearance. is attained.

The marginalportibn ltofthe tack @over sheet.l 1 surr-cnin'dngY the holesA 9'` the latter project" transversely' into the inner' ends ci?v the noi-'es t0 and profeet' from' the inner'margins of the walls surrounding the latter. The marginal portions I5 thus form inwardly projecting fibrous flanges at the inner ends of the apertures B, such as to oppose the flow of plaster through the apertures B and yet allow a modicum of plaster to pass to the back of the board through the openings 9 in the back cover sheet to effect anchorage of the latter as indicated in Fig. 4.

In order to reinforce the marginal portions I5 and strengthen them against being pressed away from the inner margins of the walls surrounding the holes I0 they are curved in section with their inner margins extended into the holes I0 toward the outer ends thereof.

Annular ribs I6 are formed on the back cover sheet 1 in slightly spaced relation to the base apertures B. In order to eect imbedding of the inturned -10 jected to the pressure of plaster directed into the portions of the back cover sheet surrounding the holes in said sheet project transversely from the adjacent margins of the Walls surrounding the holes in the plaster layer into the path of plaster delivered to the apertures to restrict iiow of plaster through the apertures; the projecting marginal sheet portions surrounding the holes in the back cover sheet being curved in section into the holes in the plaster layer to oppose thrust of plaster pressed thereagainst from the interior of t-he holes in the plaster layer.

.- 2. In a lath lboard having a layer of plaster and a fibrous back cover sheet with axially aligned flanges II or flap I4 and the reinforcing ribs ,I64

in the plaster layer 5, they are pressed into the plaster layer while the latter is inafsoftorplastic state and while the brous coversheets are a 1 moist state.

holes in the cover sheet and plaster layer forming plaster receiving holes through the lath board,

the back cover sheet being formed with arcuate The apertures B are preferably circular and the l holes I are preferably tapered to diverge outwardly from ther-front coversheet ktoward the back cover sheet'l.` On applying a'plaster will displace air in the latter which passes to the back of the board through the holes' 9'so as to permit complete lling of the aperturesy with the plaster, While'a small portion of -thefplaster will be passed through the holes 9 and will flow over the outer faces ofat least portions of theA marginal portions I5 of the coversheet surrounding the holes 9 such as to anchor the portions I5 in the applied plaster asindicated at- I in Fig. 4,

thus eecting a -bond between the applied plaster and the marginal portions I5 ofthe sheet sur' rounding the holes in the back cover sheet.

By forming the front cover sheet 5 vwith the inturned margins I Isurrounding the holes 8 and by providing the annular ribs I6 around the holes 9 in the back cover sheet I the cover sheets'and the assembled board4 are strengthened against bending across the weakened areas or lines occasioned by rernoval'oi` the material necessary`v in forming the apertures'B. This enables the formation of the apertures-B of larger cross section relative to the thickness of the board than wouldV 4body c tol-the face ofthe board as shown in Figa 4, portions of the.` plaster will enter the apertures 4B and in so doing 1; In a lath board embodying a, plaster layer,v

interposed between a fibrous iront cover sheet and a back cover sheet having plaster-receiving apertures extending therethrough formed by axally'aligned holes inysaid sheets and plaster layer, the construction in which 'the marginal embedded'in the plaster. layer with portions of the back cover sheet projecting inwardly from y the ribs into the holes of the plaster layer.

3; VA lath board in which a plaster layer is interposed between a front cover sheet and a iibrous back cover sheet and having plaster receiving apertures therein comprising holes leading through the plaster layer and through the cover sheets in axial alignment with each other, the holes in the plaster layer being tapered from the back cover sheet toward the front cover sheet, the marginal sheet portions surrounding the holes in the front cover sheet fbeing turned inwardly against the walls surrounding the holes in the plaster layer, the back cover sheet having annular ribs which encircle the holes therein and in the plaster layer and are directed into and embedded in the plaster layer with portions of the back cover sheet projecting inwardly from the ribs and into the holes of the plaster layer.

GEORGE A. BUTTRESS.

' REFERENCES CITED v The vfollowing references are of record in the ille lof vthis patent:

y UNITED STATES PATENTS Number Name Date 1,203,757' Linkletter Nov. 7, 1916 1,268,802 Schumacher June 4, 1918 1,327,446 Schumacher Jan. 6, 1920 1,430,080 Hicks Sept. 26, 1922 1,954,671 Inman et al Apr. 10, 1934 1,995,393 Manske Mar. 26, 1935 2,323,564 Page July 6, 1943 FOREIGN PATENTS Number Country Date 49,374 Switzerland Dec. 27, 1909 128,994 Great Britain July 10, 1919 

